CN108832643A - A phase commutation system of an intelligent phase commutation switch - Google Patents

Abstract

The invention discloses a phase change system of an intelligent phase change switch, which comprises a first switch, a second switch and a third switch, a static contact of the first switch is connected with phase A and the sixth switch, and The other static contact connects phase B and the seventh switch, the moving contact of the first switch connects a static contact of the second switch, the other static contact of the second switch connects phase C and the eighth switch, and the sixth switch The other end of the seventh switch is connected to the ninth switch, and the other end of the seventh switch is connected to the tenth switch. The invention has simple logic implementation, can realize zero-voltage shutdown and zero-current conduction, has shorter load power-off time, lower implementation cost, and can effectively solve the control problem of three-phase load rebalancing in the distribution station area.

Description

A phase commutation system of an intelligent phase commutation switch

technical field

The invention relates to the field of electric power transmission, in particular to a phase change system of an intelligent phase change switch.

Background technique

China's mountainous area is vast, with many and scattered power users, and there are a large number of single-phase loads with unbalanced temporal and spatial distributions, resulting in varying degrees of unbalanced three-phase loads in most distribution stations. The impact of unbalanced three-phase load on distribution sub-area mainly includes four aspects: 1) increase of distribution transformer and line loss; The output of the electric transformer is reduced, and the efficiency of electric energy conversion is reduced; 4) The unbalanced operation of the three-phase load causes the zero-sequence current of the distribution transformer to increase, and the resulting eddy current loss increases the operating temperature of the distribution transformer, endangering its safety and life. Therefore, it is an urgent problem to realize the rebalancing of the three-phase load in the distribution station area and improve the economic operation level and the quality of the power supply voltage in the distribution station area.

Contents of the invention

The purpose of the present invention is to provide a commutation system of an intelligent commutation switch to solve the problems raised in the above-mentioned background technology.

To achieve the above object, the present invention provides the following technical solutions:

A phase change system of an intelligent phase change switch, comprising a first switch, a second switch and a third switch, one static contact of the first switch is connected to phase A and the sixth switch, and the other static contact of the first switch Point B is connected to the seventh switch, the moving contact of the first switch is connected to one static contact of the second switch, the other static contact of the second switch is connected to C phase and the eighth switch, and the other end of the sixth switch is connected to The ninth switch, the other end of the seventh switch is connected to the tenth switch, the other end of the eighth switch is connected to the eleventh switch, the moving contact of the second switch is connected to the other end of the fourth switch and the third switch, and the other end of the fourth switch The other end is connected to the other end of the fifth switch.

As a further technical solution of the present invention: the fourth switch, the sixth switch, the seventh switch and the eighth switch are all bidirectional thyristors.

As a further technical solution of the present invention: the third switch, the fifth switch, the ninth switch, the tenth switch and the eleventh switch are ordinary relays.

As a further technical solution of the present invention: a single-pole double-throw relay for the first switch and the second switch.

As a further technical solution of the present invention: the other end of the ninth switch is connected to the other end of the tenth switch, the other end of the eleventh switch, the other end of the third switch, the fifth switch and the live line L.

Compared with the prior art, the beneficial effects of the present invention are: the logic of the present invention is simple to implement, zero-voltage shutdown and zero-current conduction can be realized, the load power-off time is shorter, the implementation cost is lower, and the power distribution station can be effectively solved. The control problem of three-phase load rebalancing in the district.

Description of drawings

Fig. 1 is a topological structure diagram of the present invention.

Fig. 2 is a circuit diagram of state 1 of the present invention.

Fig. 3 is a circuit diagram of state 2 of the present invention.

Fig. 4 is a circuit diagram of state 3 of the present invention.

Fig. 5 is a circuit diagram of state 4 of the present invention.

Fig. 6 is a circuit diagram of State 5 of the present invention.

Fig. 7 is a circuit diagram of state 6 of the present invention.

Fig. 8 is a circuit diagram of state 7 of the present invention.

Fig. 9 is a circuit diagram of state 8 of the present invention.

Fig. 10 is a circuit diagram of state 9 of the present invention.

Figure 11 is a circuit diagram of State 10 of the present invention.

FIG. 12 is a waveform diagram before and after reverse phase sequence switching in FIG. 12 .

FIG. 13 is a switching process diagram of zero-voltage turn-off and zero-current turn-on.

Detailed ways

The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some, not all, embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

Please refer to Figures 1-3. Numbers 1-10 in the figure correspond to the first switch - the tenth switch in turn. Embodiment 1: A commutation system of an intelligent commutation switch. The detection points of voltage and current are shown in Fig. 1 . Thyristors and relays are both considered switches. When the first switch is off and the second switch is off, it means that phase A is on; when the first switch is on and the second switch is off, it means that phase B is on; when the second switch is on, it means that phase C is on. Positive phase sequence switching includes switching from phase A to phase B, switching from phase B to phase C, and switching from phase C to phase A. Reverse phase sequence switching includes switching from phase B to phase A, switching from phase C to phase B, and switching from phase A to phase C. The reverse phase sequence switch is converted into two positive phase sequence switches, and the time interval between the two switches is greater than 60s. For example, switch from phase B to phase A, then switch from phase B to phase C, wait for more than 60s, and then switch from phase C to phase A.

The switching process of the positive phase sequence is illustrated by taking the switching process from phase A to phase B as an example, and other switching processes are similar.

① State 1: The third switch is closed, and the other switches are open. Corresponding to Figure 2.

②Status 2: Make sure the initial position is on phase A through the feedback contact, if there is no voltage between the fourth switch and the fifth switch and between the seventh switch and the tenth switch within 12ms, then close the fifth switch and the tenth switch . If a fault occurs, fault action: no action, stop directly at state 1. State at this time: the third switch, the fifth switch and the tenth switch are closed, and the rest are open, corresponding to Fig. 2 .

③State 3: Wait for 10ms, close the fourth switch and open the third switch. Use the feedback contact to judge whether the breaking of the third switch is successful. If there is a fault, turn off the fifth switch and the tenth switch, and roll back to state 2. State at this time: the fourth switch, the fifth switch and the tenth switch are closed, and the rest are open, corresponding to FIG. 4 .

④ State 4: first block the pulse of the fourth switch (disconnect the fourth switch). In case of failure, open the fourth switch and close the third switch, and roll back to state 3. State at this time: the fifth switch and the tenth switch are closed, and the others are open, corresponding to Fig. 5 .

⑤Status 5: Detect the current of the load at the position of the thick line, the thyristor will be turned off naturally at the zero crossing point, and the load will be powered off. Closing the seventh switch waits for the voltage zero crossing to be turned on naturally. In case of failure, close the fourth switch and roll back to state 4. State at this time: the fifth switch, the seventh switch, and the tenth switch are closed, and the rest are open, corresponding to FIG. 6 .

⑥State 6: the first switch is closed. Judge whether the moving contact of steady-state relay 1 is switched correctly. Otherwise, reverse restore its initial running state. State at this time: the first switch, the fifth switch, the seventh switch, and the tenth switch are closed, and the rest are open, corresponding to FIG. 7 .

⑦ State 7: Compare the voltage at the position of the thick line through the XOR gate circuit. The fourth switch is closed as in phase. Otherwise, reverse restore its initial state. In case of failure, disconnect 1 and roll back to state 6. State at this time: the first switch, the fourth switch, the fifth switch, the seventh switch, and the tenth switch are closed, and the rest are open. Corresponding to Figure 8.

⑧Status 8: switch off the seventh switch and the tenth switch. At this moment, the load supplies power through the fourth switch and the third switch branch. During fault operation, turn off the fourth switch and roll back to state 7. State at this time: the first switch, the fourth switch, and the fifth switch are closed, and the rest are open, corresponding to FIG. 9 .

⑨Status 9: Close the third switch, and confirm that the third switch is closed through the feedback contact. Close the seventh switch and the tenth switch in case of failure, roll back to state 8. State at this time: the first switch, the third switch, the fourth switch, and the fifth switch are closed, and the others are open, corresponding to FIG. 10 .

⑩Status 2: Turn off the fourth switch and the fifth switch. Turn off the third switch in case of failure, and roll back to state 9. State at this time: the first switch and the third switch are closed, and the others are open, corresponding to Fig. 11 .

According to this logic, zero-voltage turn-off and zero-current turn-on can be realized.

Embodiment 2: On the basis of Embodiment 1, the fourth switch, the sixth switch, the seventh switch and the eighth switch in this design are all bidirectional thyristors. The third switch, the fifth switch, the ninth switch, the tenth switch and the eleventh switch are common relays. The single pole double throw relay of the first switch and the second switch adopts the above switch, which not only has low production cost, but also is convenient to use, easy to operate and good in stability.

The specific implementation method of this user: 1. Detect the unbalance degree of the three-phase current. If the unbalance degree is >15%, the unbalance degree after phase sequence switching is lower than the current unbalance degree, and the current is between 1A and 50A. During the time, the phase change switch is allowed to perform automatic phase change, and the load is switched from the current phase to the minimum load phase.

2. According to the above logic of state 1 to state 10, commutation switching is performed. Reverse phase sequence switching shall be transformed into two positive phase sequence switching with an interval of not less than 60s;

3. After the switching is completed, re-detect the unbalance degree, and if the unbalance degree has not decreased, return to the initial state;

4. After the switching is completed, it is not allowed to switch again within 2s.

It will be apparent to those skilled in the art that the invention is not limited to the details of the above-described exemplary embodiments, but that the invention can be embodied in other specific forms without departing from the spirit or essential characteristics of the invention. Accordingly, the embodiments should be regarded in all points of view as exemplary and not restrictive, the scope of the invention being defined by the appended claims rather than the foregoing description, and it is therefore intended that the scope of the invention be defined by the appended claims rather than by the foregoing description. All changes within the meaning and range of equivalents of the elements are embraced in the present invention. Any reference sign in a claim should not be construed as limiting the claim concerned.

In addition, it should be understood that although this specification is described according to implementation modes, not each implementation mode only contains an independent technical solution, and this description in the specification is only for clarity, and those skilled in the art should take the specification as a whole , the technical solutions in the various embodiments can also be properly combined to form other implementations that can be understood by those skilled in the art.

Claims (5)

1. a kind of commutation system of intelligence phase-change switch, including first switch, second switch and third switch, which is characterized in that The stationary contact connection A phase and the 6th switch of the first switch, another stationary contact of first switch connect B phase and the 7th Switch, first switch movable contact connection second switch a stationary contact, second switch another stationary contact connection C phase and 8th switch, the 9th switch of other end connection of the 6th switch, the tenth switch of other end connection of the 7th switch, the 8th switch The 11st switch of other end connection, the other end of movable contact connection the 4th switch and third switch of second switch, the 4th switch The other end connection the 5th switch the other end.

2. a kind of commutation system of intelligent phase-change switch according to claim 1, which is characterized in that the 4th switch, 6th switch, the 7th switch and the 8th switch are bidirectional thyristor.

3. a kind of commutation system of intelligent phase-change switch according to claim 1, which is characterized in that the third switch, 5th switch, the 9th switch, the tenth switch and the 11st switch are common relay.

4. a kind of commutation system of intelligent phase-change switch according to claim 2, which is characterized in that the first switch and The single-pole double-throw relay of second switch.

5. a kind of commutation system of intelligent phase-change switch according to claim 3, which is characterized in that the 9th switch The other end, the 5th switch and the firewire that the other end of the tenth switch of other end connection, the other end of the 11st switch, third switch L。